Annealing processes of vacancy-type defects in electron-irradiated and as-grown 6H-SiC studied by positron lifetime spectroscopy

Abstract

Annealing processes of vacancy‐type defects in 3 MeV electron‐irradiated and as‐grown 6H‐SiC have been studied by positron lifetime spectroscopy. Vacancy‐type defects giving rise to a positron lifetime of 183 ps were detected in as‐grown n‐type specimens. They were found to be annealed at around 1400 °C and were related to silicon vacancies, possibly complexes of silicon vacancies and nitrogen atoms. Defects related to carbon vacancies, silicon vacancies, and divacancies were found to be created by electron irradiation. The defects related to carbon vacancies and divacancies were found to be annealed up to 500 °C. The defects related to silicon vacancies were found to be annealed at around 750 and 1400 °C. The former annealing stage was inferred to be due to migration of silicon vacancies to internal sinks or nitrogen atoms to form complexes of silicon vacancies and nitrogen atoms. The latter annealing stage was explained as due to annihilations of the complexes as well as the case of as‐grown specimens.